The objective of this study is to assess the safety of the buprenorphine transdermal system (5, 10, and 20 mg) in comparison to placebo transdermal system in subjects with moderate to severe pain after orthopedic surgery. The double-blind treatment intervention duration is 72 hours during which time supplemental analgesic medication (intravenous morphine PCA) will be provided to all subjects in addition to study drug.